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NITE STATES ArRN'r Grimes.

CHARLES s. LOOKWOOD, OF ALBANY, NEW YORK, AND JOHN w. HYATT, or NEWA K,NEW JRRsEY, ASSIGNORS TO THE RoNsILATR COMPANY, (LIMITED,) OF ALBANY,NEW YORK.

PLASTIC MATERIAL TO IMITATE IVORY, 80C.

SPECIFICATION forming part of Letters Patent No. 305,205, datedSeptember 16, 1884.

Application filed March 18, 1884. (No specimens.)

To all whom it may concern.-

Be it known that we, CHARLES S. LOOKWOQD, a citizen of the UnitedStates, and a resident of Albany, in the county of Albany and State ofNew York, and JOHN WV. HYATT, a citizen of the United States, residingat Newark, New Jersey, have invented certain new and useful Improvementsin Plastic Material to Imitate Ivory, &c., of which the following is aspecification.

The invention has relation to an improved process of producing articlesof factitious material.

It consists, essentially, in the discovery that 1 if certain kinds ofsubstances are sufficiently coinminuted the powder will form, whensubjected to heat and pressure, a homogeneous mass without the use ofadhesives or other ingredients of an analogous nature. Ve havediscovered that if the particles are sufficiently fine they will, whensubjected to heat and pressure in a mold,be united to form an article ofexceptional value.

It has heretofore been customary to produce Q5 articles of commerce bysubjecting powders of different kinds to treatment in heated molds;

but in no instance has the discovery that we make available beenutilized. 011 the contrary, in every instance an adhesive agent has beenemployed, or the adhesive nature of some one or more of the elementscomposing the powder has been relied upon to cause the particles toadhere together. vOur invention proceeds upon a different theory-namely,that 5 if the substance is sufliciently comminuted the adhesion may befully effected without the addition of any adhesive agent of any kind,and this although the substance may be entirely without any of thequalities of what are 40 commonly known as-adhesive agents.

The kinds of substances which we have here tofore used may be defined asthose which are generally classified as organic, and especially such ashave what is known as a cellular 5 structure. Among the materials whichwe have used with particularly satisfactory results are bone, horn,wood, paper, leather, 850., all of which are found to possess in aneminent degree the qualities which seem to be of value in theeifectuation of our process. It is not impossible, however, that othermaterials can be successfully empldyed, and that only what are known asstrictly inert substances are to be avoided. Indeed, it is not possibleto define with certainty the class of substances in connection withwhich the process may be successfullypracticed. Whatever substance ormaterial is of such a nature that the particles will flow or bemollified when subjected.

to pressure 'in a die heated to, say, three hundred and fifteen degrees(315) Fahr enheit is subject more or less to the principle which we havediscovered. We do not limit Ourselves, therefore, to materials which arestrictly organic, although weprefer 6 5 and recommend some form ofmaterial or sub stance similar in its nature and structure to thosewhich we have enumerated.

It is essential, as has been stated, that cominiuution of the materialbe carried sufficiently 7O far to effect a very advanced separation ofthe elements. It is not practicable for us to define with entireaccuracy the size of the particles which is most desirable but we areable to say that if the comminution is carried so far that the particlesare about one twentythousandth of an inch in size a perfectlysatisfactory result will be attained. If the substance or material isstill further reduced, the result will not be less satisfactory, while agood result will be produced even if the partioles'are not all carriedas far as the point which we have indicated. The size which we give isintended as an illustration to facilitate the practicing of theinvention by others skilled in the art,and 8 5 not as an exact and invariable definition from which there is to be no departure. Our experience leads us to believe that the size which we have indicatedto wit,about one twentythousandth of an inch-is to be preferred, but 0particles somewhat larger may be used, while any further reduction willnot prejudice, but rather tend to enhance, theresult. The comminutionmay be effected by means of a mill or otherwise, as may be desired, theonly essential 5 consideration being that the material be sufficientlyreduced, and that at the time it is introduced into the molds it besubstantially free from moisture. In grinding or reducing the materialgreat pains will be taken to effect a thorough comminution, as aconsiderable difference in the size of the particles will cer tainlyprejudice, if it does absolutely prevent,

the attainment of an entirely satisfactory re sult.

The invention may be practiced in connection with the production of alarge variety of articles, and especially that class of articles whichresemble in appearance ivory,0r which are made of rubber and likematerials. The powder .may be colored by the use of pigments ofdifferent kinds, which may be intro duced by combining them withwater-repellents or gums, or otherwise, according to metlr ods wellunderstood in the art to which the invention relates. After the materialor substance has been reduced, as hereinbefore described, it will besubjected to heat and pressure in dies of ordinary construction,thepressme being about, say, from one thousand to three thousand poundsper square inch, and the heat about 315 Fahrenheit, which will beslightly varied, according to circumstances,

as will be readily understood by persons skilled in the art.

\Vhat we claim as our invention, and desire to secure by Letters Patent,is

The process herein described of forming articles of organic or analogoussubstances which consists in comminuting thesubstance or material, ashereinbefore set forth, and then subjecting the comminuted substance tothe action of heat and pressure in a mold.

Signed at Albany, in the county of Albany and State of New York, this7th day of March, A. D. 1884, by CHARLES S. LooKwooD.

. CHARLES S. LOOIUVOOD.

Witnesses:

DAVID M. KINNEAR, JOHN R. FORAN.

Signed at New York, in the county and State of New York, by JOHN W.HYA'r'r, this 15th day of March, 1884.

JOHN V. HYATT.

XVitnesses to signature oi. John Hyatt:

CHAS. O. GILL, I llnmL-x N (1 Us'row.

